Annex IV (entered into force 27 Sept, 2003)contains a set of regulations regarding the discharge of sewage into the sea from ships, including regulations regarding the ships’ equipment and systems for the control of sewage discharge, the provision of port reception facilities for sewage, and requirements for survey and certification.
It is generally considered that on the high seas, the oceans are capable of assimilating and dealing with raw sewage through natural bacterial action. Therefore, the regulations in Annex IV of MARPOL prohibit the discharge of sewage into the sea within a specified distance from the nearest land, unless otherwise provided.
- Drainage and other wastes from any form of toilets and urinals.
- Drainage from medical premises via wash basins, wash tubs and scuppers located in such premises.
- Drainage from space containing living animals.
- Other waste waters when mixed with the drainages defined above.
Holding tank: means a tank used for the collection and storage of sewage.
International voyage : means a voyage from a country to which the present convention applies to a port outside such country or conversely.
Person means member of the crew & passengers.
Anniversary date: means the day and the month of each year which will correspond to the date of expiry of the international sewage pollution prevention certificate.
Applicability of Annex IV
Annex IV will apply to following ships on international voyages-
- New ships of 400 GRT & above
- New ships of less than 400 GRT which are certified to carry more than 15 persons.
- Existing ships of 400 GRT & above, 5 years after the date of entry into force of this annex. (27 Sept, 2003)
- Existing ships of less than 400 GRT which are certified to carry more than 15 persons, 5 years after the date of entry into force of this annex.
Special Area: Baltic Sea
Sewage discharge Regulations :
- The ship is to discharge commentated and disinfected sewage using an approved system at a distance of more than 3NM from the nearest land or sewage which is not comminuted or disinfected at a distance of more than 12NM.
- Sewage from holding tank should not be discharged instantaneously but a moderate rate when the ship is en route and proceeding at not less than 4 Knots.
- The ship has in operation an approved sewage treatment plant which has been certified by the administrations.
- The test results of the plant are laid down in the ships international sewage pollution prevention (ISPP) certificate.
- Additionally the effluent shall not produce visible floating solids nor cause discoloration of the surrounding water.
Comminutor : It is to cut the sewage materials at a size of less than 25 mm.